tree 69a5e7033cac2afad415eacbf0c8e6d9171db8d4
parent b331747f2267425367a56b638efbc5b563d43ad7
author Paul Berry <paulberry@google.com> 1657640202 +0000
committer Commit Bot <commit-bot@chromium.org> 1657640202 +0000

Flow analysis: remove `Reference` type hierarchy.

Previously, flow analysis used the class `ReferenceWithType` to track
references for which it knew the type, and `Reference` (and its
subclasses) to track references for which it didn't know the type (or
for which the type was unimportant).

This change removes the `Reference` class hierarchy, in favor of just
using the integer promotion keys.  This should reduce the number of
memory allocations that flow analysis needs to make.

A few pieces of information previously maintained by the `Reference`
class hierarchy are now tracked elsewhere: the logic for computing
non-promotion reasons is now in
`_FlowAnalysisImpl._getNonPromotionReasons`, and the property name and
property member (previously maintained by `_PropertyGetReference`) is
now maintained by `_PropertyReferenceWithType` (a new subclass of
`ReferenceWithType`).

Bug: https://github.com/dart-lang/language/issues/2020
Change-Id: I72f2d80b3256bf8b9c9a30bcc55666ecb7c31e47
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/250242
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>